Added grammer rules and classes for Bool and Str
Fixed grammer mistakes and generated new parser
Forgot to add files
Added generics to Expr types
Revert "Added generics to Expr types"

This reverts commit 4a71ebd3e8f2e1abe75fb6029b173bd5f989977d.
Re-added antlr library
Pulled some more superclasses up.
Made some more refactorings
Worked further on questions and conditionals
Implemented computation, now for some more unit tests.
Removed unused imports.
Fixed bug in ANTRL-syntax: used '<=' instead of '-'.
Form is now the starting symbol of the language. Created helper functions in TestParser superclass for easily testing forms, statements and expressions.
Expanded the tests for the if-statement parser.
Refactored some more
Splitted out and added some more unit tests
Added check if the condition of an if-statement is of type boolean.
branch test

branch test ruudvanderweijde
removal of jacc
added antlr 3.5